Duke University scientists have used the self-assembling properties of DNA to mass-produce nanometer-scale structures in the shape of 4×4 grids, on which patterns of molecules can be specified.

They said the achievement represents a step toward mass-producing electronic or optical circuits at a scale 10 times smaller than the smallest circuits now being manufactured.

The smallest features on these square DNA lattices are approximately 5 to 10 nanometers, compared with about 55 to 65 nanometers in silicon circuits created using photolithography.

To create the tiny DNA grids, the researchers began with tiny building blocks they called “tiles.” Each tile was made up of strands of DNA bent like pipe cleaners into the shape of a cross. In the middle of each cross was a loop of DNA that can be attached to another molecule that can in turn bind to a protein molecule to give the tile a tag visible by AFM. Each arm of the cross, about 10 nanometers long, had a pair of “sticky ends” where the DNA strand was made of up of unpaired bases that tend to bind with reciprocal bases. Tiles with complementary sticky ends link together when mixed.

The structure of the tiles created the molecular equivalent of puzzle pieces that would self-assemble only in a specific arrangement when mixed together, with the DNA loop loaded with a desired “cargo” molecule that would form the structure the researchers wished to create.

Source: Duke University news release